[targa88]

First off- totally stock car(1988)- passed two years ago ( last test). However, I suspect that the high octane gas used for track days has "clogged" the O2 sensor.Which is causing the over limit C02 readings.
By process of elimination, the spark plugs appear, so the next component would be the sensor. I have emptied the fuel tank of the high octane gas, and will proceed will lower octane.
1) IS there any way of cleaning the O2 sensor?
2) IF not, how complicated is the replacement? Are there any speciality tools required (I think that I read 22mm crows foot wrench)?
3) Any secrets, I need to know before starting?
Much appreciated.